Peter Duniho wrote:
"Guy Elden Jr" wrote in message
oups.com...

Something I've always wondered... why do TRSAs even exist? Seems like a
dangerous proposition to choose some airports as having the concept of
a voluntary controlled airspace? Why not a Class C (their closest
cousin as far as I can tell)?


They are left-over from when Class C airspace was called an ARSA.

The predate ARSA's. TRSA's existed when there were only TCA's nad the
FAA hadn't invented ARSA's.

TRSA's are NOT controlled airspace in themselves. Just wannabe radar
service zones.

The main
difference between an ARSA and a TRSA was that the former required
participation, while the latter did not. Then, and now, the TRSA is sort of
"in-between" Class C (mandatory radar services) and Class D (no radar
services).

It's not an inbetween anything. It's not a class of controlled
airspace. Just a charted area where you could get radar services
(which isn't limitted to TRSA's by the way, we have some airports
in the area with approach controls in their class D's that bear
at most a telltale R in their sectioanl data bock).